In traditional mechanisms, deficiencies have been observed; one of them is derived from the formation of surface scum or dross on ingots or billets which normally must be removed, and the other of these deficiencies stems from the breakage of the billet mould when it comes in contact with a billet not removed from the mould. All this usually makes it necessary to construct complex, noisy automated devices, in order to avoid the above-mentioned deficiencies.